The present invention relates to a portable circuit interrupting apparatus of the type used to open high voltage circuit isolating devices, such as fuse cutouts, disconnecting switches, power fuses, and the like.
Circuit isolating devices of the described type are adapted to be periodically opened to provide necessary service, such as fuse replacement or service to the power lines. Conventionally, such circuit isolating devices include a ring-like conducting part and a hook-like conducting part which are relatively movable between a contacting position for establishing a closed circuit through the device, and a separated position for establishing an open circuit through the device.
When it is necessary to open the circuit isolating device while it is carrying load current, an arc is drawn between the two conducting parts, which is likely to damage any components which are contacted by the arc. Also, where other adjacent circuits are involved, the drawn arc may jump to another circuit, causing a fault in the other circuit. Still further, the drawn arc can jump to the operator, causing serious injury.
To minimize the risks and dangers associated with the opening of such circuit isolating devices, specially designed portable circuit interrupting apparatuses have been developed, as described for example in U.S. Pat. Nos. 2,816,984 and 2,816,985. These apparatuses typically comprise a rod-like terminal which enters the ring-like conducting part of the isolating device and a second terminal which loops about the hook-like conducting part. The interrupting apparatus is mounted at the upper end of an elongate line pole, and in use, the operator initially lifts the apparatus to an elevated position adjacent the isolating device while holding the lower end of the line pole, and the operator then swings the interrupting apparatus into engagement with the isolating device so as to bring the two terminals of the interrupting apparatus into proper contact with the two conducting parts of the isolating device. Upon then pulling downwardly on the line pole, the operator is able to separate the two conducting parts of the isolating device to open the circuit and so that the current then flows through a shunt circuit which is located in the interior of the interrupting apparatus. The interrupting apparatus further incorporates a shunt circuit interrupter, which opens the shunt circuit inside the apparatus, and so that the resulting arc is confined to the interior of the apparatus.
The interrupting apparatuses of the type described above and as illustrated and described in the above-referenced patents, must be carefully manipulated during their initial engagement with the isolating device, so that the two terminals properly engage the two conducting parts of the isolating device. This typically requires the hook engaging terminal of the interrupting apparatus to initially engage the hook-like conducting part of the isolating device, and the interrupting apparatus is then swung laterally so that the ring engaging terminal of the interrupting apparatus enters the ring-like conducting part of the isolating device. Thus, a two-step movement of the interrupting apparatus is required to properly engage the two terminals with the two conducting parts of the isolating device. This can be difficult in actual practice, since the operator will often be required to carefully manipulate the apparatus while it is located several feet above the operator and on the upper end of the line pole.
A further disadvantage of the present interrupting apparatuses is the fact that they are sized to match the size of a particular isolating device, and thus a separate and properly sized interrupting apparatus is required for differently sized isolating devices.
It is accordingly an object of the present invention to provide a circuit interrupting apparatus of the described type which significantly alleviates the above noted disadvantages and limitations of the prior art apparatuses.
It is a more particular object of the present invention to provide a circuit interrupting apparatus and a method of utilizing the same and wherein the apparatus may be joined to the isolating device with a simple lateral thrust of the apparatus toward the isolating device, and wherein the ring engaging terminal initially enters the ring-like conducting part, and thereafter serves to guide the hook engaging terminal into operative engagement with the hook-like conducting part of the isolating device as the lateral thrust continues.